The units of data (the logical block lengths) in Hard Disk Drives (HDDs) vary depending on the intended use of the system, in addition to the unit of 4K bytes compatible with the HDDs shifted to the advanced format, and the unit of 512 bytes (512-byte emulation) for maintaining the compatibility with existing systems. When a system uses an HDD, the format change (initialization) of the HDD is required such that the logical block length of the HDD is compatible with the system.
However, the format change requires the rewriting of the recoding area of the magnetic disk. It takes time to rewrite the recoding area with the increase in capacity of the HDD.